[carton253]

Bombadil and the Barrow Downs serves the plot two ways. The first as you said earlier is they get the Westernesse swords. The 2nd is when Aragorn overhears Frodo tells the other Hobbits that he has to leave the name Baggins behind and use the name Underhill instead. That alerts Aragorn who Frodo is and what he carries. Then, Aragorn slips over the gate and the rest is one heck of a story...

[Overtaxed]

True. Plus they lose the Black Riders for a while with that cut through the forest. Pity those poor hobbits if the Riders followed them through the Old Forest!